Pneumatic pump

ABSTRACT

A hydraulically controlled, pneumatically powered pumping unit for pumping liquids containing settleable solids. The pumping unit includes a vessel having a top cover secured thereto in an air tight manner. A vertical discharge pipe extends through the top cover into the vessel in an air tight manner. A U-tube, positioned within the vessel with a first end in fluid communication with the discharge pipe and a second end in communication with the interior of the vessel, serves to control the operation of the pump. An inlet pipe extends through the bottom of the vessel, having an upper end positioned within the vessel at a level below the first end of the U-tube and above the curved portion of the tube, and a lower end positioned a short distance above the floor of a liquid container. An air inlet pipe extends through the top cover to supply compressed air into the vessel.

United States. Patent. 11 1- Mowen 1 ,1451 Nov. 12, 1974 PNEUMATIC PUMP [75 Inventor: John E. Mowen, Shawnee, Kans. 1221 Assignee: Filed:

App]. -No.:

Ecodyne Corporation, Chicago, 111. Apr. 30, 1973 U.S. Cl. 417/118, 417/430 Int. Cl. F041 1/06, FO4g 21/00 References Cited UNITED STATES PATENTS 1,279,580 9/1918 Peters .1. 417/118 x 1,499,589 7/1924 Navin 417/118 x FOREIGN PATENTS 0R APPLICATIONS 237,594 7/1969 u.s.s.R.....;.j. ..-..4l7/ll8 Primary Examiner -Carlton R-. Croyle Assistant Examiner-Richard E. Gluck Attorney, Agent, or Firm-Joel E. S iegel; Charles M. Kaplan Field of Search.' 417/1 18, 430

57 ABSTRACT A hydraulically controlled, pneumatically powered.

pumping unit for pumping liquids containing settleable solids. The pumpingunit includes a'vessel having atop cover secured thereto in an air tight manner. A vertical discharge pipe extends through the top cover into the vessel in an air tight manner. A U-tube, positioned within the vessel with a first end in fluid communication with the discharge pipe and a second end in communication with the interior of the vessel, serves to control the-operation of the pump. An inlet pipe extendsthrough the bottom of the vessel, having an upper end positioned within the vessel at a level below the first end of the U-tube and above the curved portion of the tube, and a lower end positioned a short distance above the floor of a liquidcontainer. An air inlet pipe extends through the top cover to supply compressed air into the'vesseL.

4 Claims, 1 Drawing Figure PNEUMATIC PUMP BACKGROUND AND SUMMARY OF THE INVENTION This invention relates to a hydraulically controlled, pneumatically powered pumping unit which is particularly suitable for pumping liquids containing settleable solids such as sewage sludge from a clarifier.

It has been the heretofore practice to use either air lift pumps or relatively complex motor driven pumps for pumping settled sewage sludge form nonmechanically cleaned clarifier units. Air lifts and pumps are subject to clogging with large solids, and there has always been difficulties in obtaining an even flow of the solid particles which settle out. Solids accumulate on the walls and floor of the clarifier and adversely affect the sewage treatment process. Previous attempts to solve this problem included continuous pumping from the clarifier at high rates to raise the ve locity into the inlet high enough to carry solids in. However, this procedure reduces the effectiveness of the treatment process, and solids still accumulate on the walls and floor leaving a path for the liquid to travel to the inlet. Another attempt to solve this problem is to suspend chains in the clarifier. Manually moving these chains at intervals disturbs the accumulations of solids, knocking them loose from the interior or the clarifier. This is not automatic and does not prevent accumulations, only removes them. Several successful mechical scraping or collecting systems are used, but they all involve powered, moving mechanisms of a relatively complex nature, and are generally classified separately when comparing types of clarifiers. v

It is an object of the present invention to provide a hydraulically controlled, pneumatically powered pumping unit having no moving parts for pumping liquids containing settleable solids from a clarifier.

Another object is to provide a pumping unit capable of handling solids in the pumped liquid and tending to be self-cleaning if clogged.

A further object of the present invention is to provide a pumping unit for pumping liquids containing settleable solids which prevents solids from settling out of the pumped liquid and accumulating on surfaces near the inlet.

A still further object is to provide a hydraulically controlled, pneumatically powered pumping unit for pumping sewage sludge from a clarifier which has no moving parts and prevents the accumulation of solids on the walls and floor of the clarifier.

The foregoing and other objects are realized in accordance with the invention by providing a pumping unit which includes a housing or vessel having a top cover secured thereto in an air tight manner. A vertical discharge pipe extends through the top cover into the vessel in an air tight manner. A U-tube, positioned within the vessel with a first end in fluid communication with the discharge pipe and a second end in communication with the interior of the vessel, serves to control the operation of the pump. An inlet pipe extends through the bottom of the vessel, having an upper end positioned within the vessel at a levelbelow the first end of the U-tube and above the curved portion of the tube, and a lower end positioned a short distance above the clarifier floor. An air inlet pipe extends through the top cover to supply compressed air into the vessel and force liquid out the discharge pipe during the pumping phase. Liquid entering and exiting the U- tube automatically switches the pump between its filling phase, pressurizing phase, and pumping phase. During the pressurizing phase, liquid is forced down the inlet pipe and strikes the floor of the clarifier and the resulting turbulence agitates the solids near the inlet pipe, preventing them from accumulating on the floor and walls of the clarifier. This backflushing feature depends upon the upper end of the inlet pipe being below the first end of the U-tube.

BRIEF DESCRIPTION OF THE DRAWING Other objects and features of the invention will become apparent to those skilled in the art as the disclosure is made in the following description of a preferred embodiment 'of the invention, as illustrated in the accompanying sheet of a drawing, in which the FIGURE is an elevation of a somewhat diagrammatic representation of a pneumatic pumping unit constructed in accordance with the present invention, shown positioned within a clarifier tank.

DESCRIPTION OF A PREFERRED EMBODIMENT Referring to the FIGURE, a pneumatic pumping unit constructed in accordance with the present invention is designated generally at 10. Pump 10 is shown positioned within a conventional clarifier tank 12 for pumping settleable solids such as sewage sludge therefrom. Although illustrated and disclosed in the environmental context of a sewage receiving clarifier, it will be readily appreciated that the hereinbelow disclosed pumping unit may be utilized in other environments which require the pumping of liquids containing settleable solids.

Pump 10 includes a closed cylindrical housing 14 having a top cover 16 and a bottom cover 18 secured thereto in an air tight relationship to form a vessel or tank 20. Top cover 16 is secured to a connecting flange 22 welded to the upper edge of housing 14 in a suitable manner such as by bolts 24. Bottom cover 18 is preferably welded to the lower edge of housing 14. Extending into vessel 20 through cover 16 is a substantially vertical discharge pipe 26. Discharge pipe 26 includes an upper section 28 which extends through and is suitably welded to an appropriate opening in cover 16 and a lower section 30 which is secured to upper section 28 by a connecting tee 32. The lower end of section 30 extends into vessel 20 to a depth approximately equal to eleven-twelfths the height of vessel 20. A U-tube or control tube 34 is formed within vessel 20 by substantially vertical pipe sections 36 and 38, substantially horizontal connecting nipples 40 and 42, and ninety degree elbows 44, 45, and 46. Connecting elbow 44 is secured to tee 32 by connecting nipple 40 whose ends are respectively received therein. The upper end 48 of pipe section 36 is received within elbow 44 and the lower end 50 of pipe section 36 extends downward for receipt within connecting elbow 45 positioned, at a level slightly above equal to the level of the lower endof section 30; Elbow 45 is secured to connecting elbow 46 by connecting nipple 42 whose ends are respectively received therein. The lower end 52 of pipe section 38 is received within elbow 46 and the upper end 54 of pipe section 38 extends upward to a level slightly above the lower end of upper section 28.

inlet pipe 60 extends through bottom cover 18 into vessel 20. Inlet pipe 60 includes a coupling 62 which extends through an opening in bottom cover 18 and is welded about itsperiphery thereto. An upper section 64 of inlet pipe 60 has a lower end 65 secured to coupling 62 and an upper end 66 which extends into vessel 20 to a level slightly below the level of tee 32. A lower section 68 of inlet pipe 60 has an upper end 70 secured to coupling 62 and a lower end 72 which extends down ward into clarifier tank 12 to a level a short distance above the floor of tank 12.

Communicating with an upper portion of vessel 20 is an air inlet connection 75 passing through an appropriate opening in top cover 16. An air inlet pipe 78, having a control valve 79 associated therewith, is secured at one end to connection 75 and at its other end to a conventional source of compressed air (not shown).

In operation, vessel 20 is completely submerged within clarifier tank 12 below the normal liquid level in the clarifier, indicated at A. The vessel 20, being constructed in accordance with the hereinabove disclosure, is substantially air tight except for the continuous flow of pressurized air which-enters vessel 20 through air inlet pipe 78. At the beginning of the operating cycle, with the liquid level within vessel 20 at the level indicated at B, liquid from outside vessel 20 flows thereinto by gravity through inlet pipe 60. This flow rate is designed to be greater than the average rated flow of the pumping unit such that thehigh velocity of the liquid entering lower section 68 draws solid particles into vessel 20. This filling part of the operating cycle continues until the liquid level inside vessel 20 reaches the level indicated at C. At this point, liquid begins flowing into U-tube 34 to seal the bottom thereof and thereby prevents the air entering vessel 20 from exiting through U-tube 34 and discharge pipe 26. This trapped air thus begins to pressurize vessel 20. This increasing pressure within vessel 20 forces liquid back down inlet pipe 60 until the level of liquid within vessel 20 reaches the level indicated at D. This liquid forced back down inlet pipe 60 strikes the floor of clarifier tank 12 and the resulting turbulence agitates the solids near inlet pipe 60, preventing them from accumulating on the floor and walls of the clarifier.

After the internal liquid level within vessel 20 reaches level C, it continues to lower, but no more liquid can go down inlet pipe 60 and it is therefore forced up through lower section 30 and upper section 28 of discharge pipe 26 and out vessel 20. When the liquid level in vessel 20 reaches level B, the liquid is forced from the bottom of U-tube 34 and vessel 20 is vented to atmosphere through U-tube 34 and discharge pipe 26. The operating cycle then repeats itself automatically.

The hereinabove disclosed hydraulically controlled, pneumatically powered pumping unit is a'simple device, capable of handling solids in the pumped liquid and tends to be selfcleaning if clogged. No moving parts are involved and no external control is required for operation, other than a supply of air under pressure. The back flushing portion of the operating cycle and the rapid fill rate during the intake portion of the cycle keeps solids from settling out of the pumped fluid and accumulating on the surfaces near the inlet. The back flushing feature requires that the top of inlet pipe 60 be below level C.

It should be understood, of course, that the foregoing disclosure relates to only a preferred embodiment of the invention and that numerous modifications or alterations may be made therein without departing from the spirit and the scope of the invention as set forth in the appended claims.

What is claimed is:

1. A hydraulically controlled and pneumatically powered pumping unit for pumping liquids containing settleable solids from a container, comprising:

a. a vessel constructed in a substantially air tight V manner for receiving liquid thereinto, said vessel being positioned within said container below the normal liquid level in said container;

b. a gas inlet pipe extending into said vessel through an upper portion thereof for supplying gas thereinto to pressurize said vessel, said gas inlet pipe being in communication with a continuous source of pressurized gas;

c. a discharge pipe extending into said vessel through an upper portion thereof;

d. a U-tube positioned within said vessel having a first end in fluid communication with said discharge pipe and a second end in fluid communication with an upper portion of said vessel, said U-tube serving to vent gas therethrough into said discharge pipe when not sealed by liquid confined therein and preventing the passage of gas therethrough when sealed by liquid confined therein; and

e. an inlet pipe extending through a bottom portion of said vessel, said inlet pipe having an upper end positioned below said first end of said U-tube and a lower end positioned a short distance above the bottom of said container so as to cause agitation on the bottom of the container adjacent said lower end of said inlet pipe when during normal operation of the pump unit liquid is forced out of said vessel and said inlet pipe into said container.

2. The invention as defined in claim 1 wherein said vessel includes a removable top cover and said discharge pipe and said air inlet pipe extend through said top cover.

3. The invention as defined in claim 2 wherein the bottom portion of said U-tube is positioned slighty above the same level as the lower end of said discharge tube.

4. The invention as defined in claim 1 wherein the flow rate through said inlet pipe is greater than the average flow rate through said discharge pipe so as to draw solid particles into said vessel. 

1. A hydraulically controlled and pneumatically powered pumping unit for pumping liquids containing settleable solids from a container, comprising: a. a vessel constructed in a substantially air tight manner for receiving liquid thereinto, said vEssel being positioned within said container below the normal liquid level in said container; b. a gas inlet pipe extending into said vessel through an upper portion thereof for supplying gas thereinto to pressurize said vessel, said gas inlet pipe being in communication with a continuous source of pressurized gas; c. a discharge pipe extending into said vessel through an upper portion thereof; d. a U-tube positioned within said vessel having a first end in fluid communication with said discharge pipe and a second end in fluid communication with an upper portion of said vessel, said U-tube serving to vent gas therethrough into said discharge pipe when not sealed by liquid confined therein and preventing the passage of gas therethrough when sealed by liquid confined therein; and e. an inlet pipe extending through a bottom portion of said vessel, said inlet pipe having an upper end positioned below said first end of said U-tube and a lower end positioned a short distance above the bottom of said container so as to cause agitation on the bottom of the container adjacent said lower end of said inlet pipe when during normal operation of the pump unit liquid is forced out of said vessel and said inlet pipe into said container.
 2. The invention as defined in claim 1 wherein said vessel includes a removable top cover and said discharge pipe and said air inlet pipe extend through said top cover.
 3. The invention as defined in claim 2 wherein the bottom portion of said U-tube is positioned slighty above the same level as the lower end of said discharge tube.
 4. The invention as defined in claim 1 wherein the flow rate through said inlet pipe is greater than the average flow rate through said discharge pipe so as to draw solid particles into said vessel. 